Vitamin B6 is commonly prescribed for treating depression in women taking oral contraceptives. This is because it is an important cofactor in the enzymatic syntheses of neurotransmitters such as serotonin and dopamine. By extension, it should also help with depression and mood changes experienced by women with PMS. However, studies that have investigated this benefit come up with mixed results and then there was the danger of peripheral neuropathy when high doses of vitamin B6 were used. How can vitamin B6 help reduce PMS symptoms? How strong is the evidence for its use in PMS? What is the recommended dose of the vitamin in PMS therapy? Read on to find out.

Vitamin B6 is a water-soluble vitamin and one of the B vitamins. Although it is commonly known as pyridoxine, there are actually 5 other vitamers of vitamin B6.

The other vitamers include pyridoxal 5-phosphate and pyridoxamine 5-phosphate, both of which are the bioactive forms of vitamin B6.

Vitamin B6 mostly serves as a coenzyme for a number of essential biochemical reactions in the body. It is linked to over 100 enzymes and promotes the metabolism of amino acids, lipids, and carbohydrates. This vitamin is also involved in the breakdown of glycogen and in the synthesis of glucose.

Other important roles of vitamin B6 include the biosyntheses of neurotransmitters in the central nervous system; the removal of homocysteine (a toxic intermediate of amino acid syntheses) from the blood; the promotion of hemoglobin and immune functions.

To determine vitamin B6 status, clinicians usually measure the level and activities of pyridoxal 5-phosphate.

Although vitamin B6 deficiency is not common, it can easily be caused by vitamin B12 and folic acid deficiencies. Other factors that can cause vitamin B6 deficiency are alcoholism, impaired kidney functions, and autoimmune diseases.

Chronically low levels of vitamin B6 may be present for a long time without the presence of clear symptoms.

Therefore, people with borderline vitamin B6 status or mild deficiency may silently suffer from the long-term damages of vitamin B6 deficiency.

Signs of Vitamin B6 Deficiency

Anemia

Dermatitis

Appearance of scales and cracks on the lips and in the corners of the mouth

Swollen tongue

Weakened immune system

Depression

Irritability

Convulsive seizures

The recommended daily intake of vitamin B6 ranges from 1 – 1.7 mg per day for adults. Pregnant and lactating women do have a higher need for this vitamin (about 2 mg per day).

Vitamin B6 supplements can also be used to raise vitamin B6 status. Most vitamin B6 supplements contain pyridoxine. The body absorbs vitamin B6 efficiently from both foods and supplements. However, because the vitamin is also water-soluble, it is easily eliminated in the urine.

The link between vitamin B6 supplementation and PMS can be traced back to the 1970s when the vitamin was commonly prescribed for the treatment of depression in women taking oral contraceptives.

This use has simply been extended to help treat mood disorders associated with PMS. But how can vitamin B6 provide relief for PMS-related mood changes?

Vitamin B6 is involved in the syntheses of some of the neurotransmitters that affect mood. Vitamin B6 acts as a cofactor in the production of dopamine and serotonin. These are also the most important “feel good” neurotransmitters.

Low serotonin level is a common observation during the luteal phase of women with PMS.

Because serotonin is involved in mood, memory, and sleep, vitamin B6 deficiency can cause symptoms such as irritability, forgetfulness, insomnia, anxiety, and moodiness. These are also the PMS symptoms that studies showed vitamin B6 reduced.

Therefore, it follows that vitamin B6 supplementation should help reduce these PMS symptoms. But does it?

Results from studies investigating the benefits of vitamin B6 supplementation for women with PMS are mixed. While some studies found no benefits, others found mild to significant improvements in PMS symptoms.

Currently, vitamin B6 is still officially recommended for managing PMS symptoms involving mood and emotions. It is no magic pill but it can help especially when combined with other natural supplements (calcium, magnesium, and herbs such as chasteberry) proven to help with PMS.

Researchers believe that the right dose of vitamin B6 for PMS is above 50 mg and not beyond 100 mg.

In studies, there is little to no benefit for taking very high doses of this vitamin. In addition, there are valid concerns that high doses of vitamin B6 can cause peripheral neuropathy.

Peripheral neuropathy involves nerve damage in the extremities and presents as tingling and numbness in the feet and hands.

Therefore, if you do decide to include vitamin B6 in the management of your PMS symptoms, start with 50 mg per day and then raise the dose if you find the starting dose safe and effective. However, doses above 100 mg per day are not recommended.

Alternatively, you can boost your vitamin B6 status by eating more foods rich in the vitamin.

In this 1986 study published in the journal, Human Nutrition. Clinical Nutrition, a group of researchers determined whether changes in vitamin B6 levels were responsible for PMS symptoms. For the study, the researchers recruited 19 women with PMS and 19 women without PMS to serve as a control.

Then the researchers measured the metabolic products of vitamin B6 (and tryptophan) in the blood and urine samples of the participants.

These measurements were made at different points of the women’s menstrual cycles. The results showed that PMS had no relationship with the observed cyclic changes in the women’s vitamin B6 status.

The results of this study suggest that PMS symptoms are not the result of vitamin B6 deficiency.

Then they measured serotonin levels in blood platelets in all these women and found no difference between those with PMS and those without. In addition, the researchers determined that vitamin B6 did not improve PMS symptoms.

However, it should be mentioned that this study only measured serotonin in the platelets and not in the central nervous system.

Because serotonin uptake in platelets is not the same as serotonin level in the brain, the conclusion of this study can only be taken lightly.

A 1990 study published in the Journal of the American Dietetic Association compared the effectiveness of a dietary intervention to vitamin B6 supplementation in the treatment of PMS.

The study involved 28 women with PMS and the study period was 1 month. While half of the women received 250 mg of vitamin B6 daily plus the diet, the other half only got the diet. The diet used in this study had a 50: 20: 30 ratio of carbohydrate, protein, and fat respectively.

While vitamin B6 supplementation raised the level of the vitamin, it did not significantly improve PMS symptoms compared to the diet-only intervention.

The researchers, therefore, concluded that vitamin B6 did not consistently improve PMS symptoms even though it increased vitamin B6 status.

There are a number of studies that have found vitamin B6 useful for managing PMS. It is worth noting that these studies usually find that the vitamin improved a certain set of PMS symptoms especially those involving mood and emotions.

One example of such studies is this 1989 study published in The Journal of the Royal College of General Practitioners.

After an initial baseline monitoring period of 1 month, the women were given either placebo or 50 mg of vitamin B6 per day for 3 months. Thereafter, the treatments were switched for the next 3 months. The results showed that only 32 women completed the trial.

The researchers found that vitamin B6 only improved emotional type symptoms such as irritability, depression, and fatigue.

These findings were also echoed by a 1987 study published in the journal, Obstetrics, and Gynecology.

In that double-blind, placebo-controlled study, the researchers recruited 55 women with moderate to severe PMS symptoms. After a baseline period of 1 month, the women were given either placebo or 150 mg of vitamin B6 for 2 months.

The researchers found that vitamin B6 improved PMS symptoms related to autonomic reactions and behavioral changes. The symptoms improved include dizziness, vomiting, depression, and cognitive decline.

The researchers concluded that vitamin B6 can help with PMS symptoms but should be used cautiously because of fear of toxicity with high doses of the vitamin.

This study shows that vitamin B6 can indeed help with PMS. However, it cannot help with all PMS symptoms and should be combined with other natural supplements for PMS.

A 1990 review published in BJOG: An International Journal of Obstetrics and Gynecology, analyzed the design and results of 12 controlled trials that had been done to investigate the benefits of vitamin B6 in the treatment of premenstrual syndrome.

The reviewers mentioned that these studies were limited by the number of participants involved.

However, the overall analysis showed a positive but weak support for the treatment of PMS symptoms with vitamin B6. The researchers called for better-designed studies to reach a stronger conclusion.

Almost a decade later, another group of reviewers undertook the same review and published their findings in the British Medical Journal in 1999.

The analysis included 9 trials involving 940 women with PMS. The reviewers also complained about the quality of the trials in this field of study. Even then they concluded that the evidence showed that vitamin B6 can help with PMS symptoms, especially premenstrual depression when given in doses up to 100 mg/day.

In a 2000 study published in the Journal of Women’s Health and Gender-Based Medicine, a group of researchers investigated the combined effects of vitamin B6 and magnesium supplements on PMS symptoms.

The study involved 44 women with PMS. They were divided into 4 groups and each of them assigned to one of the following 4 treatments:

200 mg of magnesium

50 mg of vitamin B6

200 mg of magnesium + 50 mg of vitamin B6

Placebo

The study spanned 1 menstrual cycle and during this period the participants were asked to keep a diary to detail the severity of 30 PMS symptoms grouped into 6 categories: anxiety, craving, depression, hydration, others and total symptoms.

The results of the study showed that the combination of magnesium and vitamin B6 produced a synergistic effect that significantly reduced anxiety-related PMS symptoms in comparison to the single use of either magnesium or vitamin B6.

This study indicates that vitamin B6 can be safely and effectively combined with other PMS supplements such as calcium and magnesium.

Such combinations will not only require lower doses of vitamin B6 (and, therefore, a lower risk of peripheral neuropathy) but also provide better results than taking only vitamin B6 supplements.